The present invention relates generally to an improved method and system for fracturing a subterranean formation to stimulate the production of desired fluids therefrom.
Hydraulic fracturing is often utilized to stimulate the production of hydrocarbons from subterranean formations penetrated by wellbores. Typically, in performing hydraulic fracturing treatments, the well casing, where present, such as in vertical sections of wells adjacent the formation to be treated, is perforated. Where only one portion of a formation is to be fractured as a separate stage, it is then isolated from the other perforated portions of the formation using conventional packers or the like, and a fracturing fluid is pumped into the wellbore through the perforations in the well casing and into the isolated portion of the formation to be stimulated at a rate and pressure such that fractures are formed and extended in the formation. A propping agent may be suspended in the fracturing fluid which is deposited in the fractures. The propping agent functions to prevent the fractures from closing, thereby providing conductive channels in the formation through which produced fluids can readily flow to the wellbore. In certain formations, this process is repeated in order to thoroughly populate multiple formation zones or the entire formation with fractures.
One method for fracturing formations may be found in U.S. Pat. No. 5,765,642, incorporated herein by reference in its entirety, whereby a hydrajetting tool is utilized to jet fluid through a nozzle against a subterranean formation at a pressure sufficient to form a cavity and fracture the formation using stagnation pressure in the cavity. In certain situations when using a hydrajetting tool, such as that described in U.S. Pat. No. 5,765,642, it may be desirable to deliver fracturing fluid into the wellbore rapidly. Further, it may be undesirable to pump certain fluids, such as fluids containing proppant, through the hydrajets. In such situations, it would be desirable to have a method and tool for delivering fluids to the formation to be fractured without delivering these fluids through the hydrajet itself.